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Groups > linux.kernel > #1611584

[RFC PATCH tip/master 3/3] kprobes: Limit kretprobe maximum instances

From Masami Hiramatsu <mhiramat@kernel.org>
Newsgroups linux.kernel
Subject [RFC PATCH tip/master 3/3] kprobes: Limit kretprobe maximum instances
Date 2017-03-29 07:30 +0200
Message-ID <tqelc-2ha-5@gated-at.bofh.it> (permalink)
References <tqelb-2ha-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Limit kretprobe maximum instance up to MAXACTIVE_ALLOC.
Without this limit, kretprobe user can specify huge number
(e.g. forget to zero-fill struct kretprobe) to maxactive
and may cause out-of-memory.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 kernel/kprobes.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 75c5390..f1bebcf 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1942,6 +1942,9 @@ int register_kretprobe(struct kretprobe *rp)
 	rp->kp.break_handler = NULL;
 
 	/* Pre-allocate memory for max kretprobe instances */
+	if (rp->maxactive > KRETPROBE_MAXACTIVE_ALLOC)
+		return -E2BIG;
+
 	if (rp->maxactive <= 0) {
 #ifdef CONFIG_PREEMPT
 		rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());

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Thread

[RFC PATCH tip/master 0/3] kprobes: tracing: kretprobe_instance dynamic allocation Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-29 07:30 +0200
  [RFC PATCH tip/master 3/3] kprobes: Limit kretprobe maximum instances Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-29 07:30 +0200
  [RFC PATCH tip/master 2/3] kprobes: Allocate kretprobe instance if its free list is empty Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-29 07:30 +0200
    Re: [RFC PATCH tip/master 2/3] kprobes: Allocate kretprobe instance  if its free list is empty Ingo Molnar <mingo@kernel.org> - 2017-03-29 08:40 +0200
      Re: [RFC PATCH tip/master 2/3] kprobes: Allocate kretprobe instance  if its free list is empty Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-29 10:30 +0200
        Re: [RFC PATCH tip/master 2/3] kprobes: Allocate kretprobe instance  if its free list is empty Josh Stone <jistone@redhat.com> - 2017-03-29 19:30 +0200
          Re: [RFC PATCH tip/master 2/3] kprobes: Allocate kretprobe instance  if its free list is empty Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-30 02:40 +0200
        Re: [RFC PATCH tip/master 2/3] kprobes: Allocate kretprobe instance  if its free list is empty Ingo Molnar <mingo@kernel.org> - 2017-03-30 09:00 +0200
          Re: [RFC PATCH tip/master 2/3] kprobes: Allocate kretprobe instance  if its free list is empty Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-30 15:10 +0200
          Re: [RFC PATCH tip/master 2/3] kprobes: Allocate kretprobe instance  if its free list is empty Alban Crequy <alban@kinvolk.io> - 2017-03-30 15:10 +0200
  Re: [RFC PATCH tip/master 0/3] kprobes: tracing: kretprobe_instance dynamic allocation fche@redhat.com (Frank Ch. Eigler) - 2017-03-29 15:30 +0200

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